Tag: cover crops

FNZ Agronomists’ Workshop – 28th November 2023

Posted on December 14, 2023 by - Farm Net Zero, Uncategorized

This event was designed for agronomists to learn about the results of some of the Farm Net Zero (FNZ) trials. Dr. Hannah Jones of the Farm Carbon Toolkit was joined by the farmers who hosted and designed the trials to discuss the findings. This event was made possible with thanks to the National Lottery Community Fund who fund the Farm Net Zero project.

Throughout the discussions, the new Sustainable Farming Incentive (SFI) payments were referred to as a potential method of reducing the risk of adopting the practices trialled by the Farm Net Zero demo and monitor farms. This report will summarise the trials presented and the discussions that followed, including the views of the agronomists present at the workshop.

Outwintering on Cover Crops

Cover crops can be useful for protecting soil by reducing erosion and nutrient leaching and preserving soil carbon stocks. In Cornwall’s mixed farming systems, cover crops can provide an opportunity for outwintering livestock in a cost-effective manner. Therefore, it is pertinent to think about the plant species included in a cover crop mix and balance up their soil health benefits with the potential feed value.

A Farm Net Zero trial was set up in winter 2021-2022, where five cover crop mixes of varying complexity were grazed by beef youngstock. Full details of the trial can be found on the Farm Net Zero Project Resources page here. The most diverse mix had the biggest improvement in soil quality, reducing compaction and attracting the most earthworms. In terms of feed value, any mixes containing black oats were the most popular with the cattle and had high dry matter, crude protein and sugars.

It was suggested that the SFI SAM2 “Multi-species winter cover” payment of £129/hectare could be used to support this practice.

Maize Establishment

FNZ Monitor Farmers, Malcolm and Catherine Barrett, have trialled different methods of establishing maize crops. In spring 2022, two fields were taken and divided into thirds – one where maize was established conventionally (plough, power harrow, drill), one cultivated with a Sumo machine, and one direct drilled with a Mzuri drill. The direct drill had the lowest fuel requirement and therefore cost. Cob weight assessments found that cobs were smallest in the ploughed area and highest where the crop was established after the cultivator. Soil sampling showed that organic matter levels dropped following ploughing, with worm numbers also reduced.

One further area of interest developed when Malcolm and Catherine noticed that the sprayed-out clover regrew in the direct drilled area. This could potentially provide nitrogen for any following crops, and so a trial was designed for the barley drilled after maize harvest. In this trial, part of the field had no nitrogen applied in order to observe any influences of the clover. Quadrat yield assessments found no significant difference between the full nitrogen fertiliser regime and the no nitrogen area and further analysis of grain nitrogen found that both the full rate and zero nitrogen well exceeded the recommended level for feed barley. This prompted discussions on the opportunities for reducing nitrogen fertiliser (and therefore reducing carbon emissions), with most of the agronomists present agreeing that this is achievable, particularly on mixed farms where livestock contribute to healthy soil. One suggestion from the group was that where soil is in good condition, nitrogen could be applied as a foliar feed direct to the plant because the healthy soil is providing good support for the plant roots.

Soil Rejuvenation after Potatoes

On FNZ Demo Farm, Ennis Barton, some ground is let for vegetable production, when this comes back in hand Andrew Brewer wants to find the fastest method of restoring soil health and returning the fields to cattle grazing. In one of the potato fields, a variety of cover crops (eligible for SAM2) were undersown with ryegrass, clovers and plantain, these were then grazed over winter. Soil quality assessments found that mixes containing Westerwolds ryegrass had the most positive effect on soil aggregate stability. However, in the following summer the Westerwolds rapidly went to seed, which made managing grazing quality a challenge. Therefore, the next best cover mix was forage rape or rye and vetch. This is another example of considering the trade-offs of mixed farming when designing systems that optimise soil quality.

Inter-Crops for Cabbages

Some of the ground rented out at Ennis Barton is used for Savoy cabbages. Following a Farm Net Zero meeting looking at managing these “risky crops”, Andrew and the cabbage growers were keen to develop methods of reducing soil erosion between the cabbage rows. A trial was designed where a mix of low-growing, deep-rooted species (chicory, plantain, white clover and buckwheat) were intersown between the cabbage rows at the beginning of October after all cabbage hoeing was completed. This trial is still being monitored, but there are hopes that intercropping will protect soil from erosion, provide feed for livestock and also reduce the amount of disease/damage to the cabbage leaf from “soil bounce” after rain. Again, this could be eligible for the SAM2 SFI payment.

Grazing Winter Cereals

Grazing winter cereals was a common practice to manage plant disease, growth rates, fertility and livestock wintering. FNZ Monitor Farmer, Anthony Ellis, tried a return to this practice on his family arable and sheep farm during winter 2022-2023. Part of a field of winter wheat was grazed with ewe lambs, with the wheat grazed right into the ground. This allowed Anthony to reduce growth regulators and fungicide and slightly reduce the nitrogen applications compared to the ungrazed remainder of the field. Septoria was reduced early in the season, but there was less difference closer to harvest as the grazed wheat caught up with the ungrazed. Some discussion followed concerning how although this is an old practice, it is now possible to put some firmer figures on the carbon savings of reduced inputs from grazing cereals.

Conclusion

Overall, this workshop for agronomists provided an excellent opportunity to share some of the project’s results so far, and to learn from agronomists who work across the project region and further afield. The ability to work collaboratively with the wider agricultural community is very valuable and helps to ensure the Farm Net Zero project reflects as many farming systems as possible.

Risky Crops

Posted on September 15, 2023 by - Insights

Certain crops (potatoes, sugar beet, maize, field vegetables) within a wider arable rotation pose increased risk of soil loss or degradation. Often described as ‘risky’ these crops may require additional management to ensure that field conditions are favourable and that there is no long-term disruption to soil functionality or structure. 

Aside from the impact upon soil, ‘risky crops’ are often those which have a potentially higher financial burden through the obstacles of production. Rising input costs, labour shortages and ever increasing inflation presents additional challenges to high-risk, high-reward crops. These two elements (soil management and economics) are additionally impacted through the changing climate with record temperatures and rainfall events.

Root crops, maize and field vegetables are often at high risk for soil degradation. The likely drastic requirements for cultivation during seedbed preparation is a vast source of emissions through direct carbon losses from soil alongside the burning of fossil fuels from machinery. Cultivating soils and the subsequent disturbance allows for greater oxidation of the soil profile, therefore promoting the fast metabolism of aerobic species of microorganisms which utilise the ‘active’ pool of soil organic matter for respiration, consequently releasing CO2 as a by-product. Furthermore, cultivation of soil which reduces the stability of the soil structure can also be at risk of direct losses of carbon bound to soil aggregates through processes such as erosion either through wind-blow, run-off or direct soil loss.  Therefore, depending upon a number of factors such as previous cropping, soil type, intensity of cultivation and moisture content, cultivated soil will lose soil organic matter at differing rates. Where land is under continual cultivation, as is much of UK arable land, reducing the frequency, depth and intensity of cultivations will reduce this soil carbon loss alongside providing alternative carbon sources as feedstock for microorganisms when cultivation is required. 

Changing the crop establishment system to reduce the frequency and intensity of cultivations will provide an immediate reduction in farm greenhouse gas emissions. Increasing organic carbon within the soil requires the building of soil organic matter through methods such as diversifying crop rotation, reducing tillage (frequency and depth) and utilising cover cropping to maintain a living root. 

Long-term rotational planning can increase the resilience of soil, using previous and subsequent cropping and management choices to minimise the impact of risky crops. To reduce the ‘risk’ of risky crops soil protection is central. Ensuring that soils are covered throughout the rotation and contain a living root for as high proportion as possible helps guard the soil from physical degradation from climatic events. Therefore, consider growing a cover crop before spring planting to scavenge nutrients over the winter period and condition soils, alongside aiming to re-plant a cover as soon as the risky crop is harvested to avoid long over-winter periods of soil erosion. Maximising the inherent soil structure and functionality throughout the rotation creates a more resilient baseline where the stresses of high cultivation, inputs and exposure to the elements occurs in high risk crops.

In grassland systems herbal leys, diverse swards and a rotational or mob grazing platform provides an excellent starting point for soils before a high-risk crop or to repair potential damage. Likewise a diverse arable rotation which incorporates cover, inter, companion or catch-cropping to protect the soil surface and provide additional rooting architecture will be a huge benefit; tired land, used to high input use, heavy cultivation and monoculture systems will be less resilient to stress (environmental, mechanical etc) than a healthy vibrant soil. 

A healthy soil is likely to provide better economic returns – with processes such as fertility, water infiltration, gas exchange, rooting capacity and nutrient availability all benefited by a well structured, high quality soil. Soil organic matter can often indicate the health of a functional mineral soil, with the higher the percentage content normally suggesting the best quality. Understanding how soil organic matter can be lost during high risk cropping processes (discussed earlier) can help to mitigate and safeguard it within the rotation. Losing soil organic matter continuously depletes the soil fertility and consequently the likely economic potential of that land. 

This blog was written by Emma Adams, one of our Farm Carbon and Soils Advisors, to read about our team head here.

More information:

For further information on species selection of cover crops and the results of the Farm Net Zero trails please see the resources below:

Outwintering on forage/cover crops

Posted on February 21, 2023 by - Farm Net Zero

A Farm Net Zero event in December 2022 at Blable Farm, Wadebridge.

Outwintering is one option for reducing costs and carbon footprint for livestock farmers, although issues can arise when outwintering unsuitable animals on unsuitable crops/soil. To address this, Farm Net Zero (FNZ) Demo Farmers, Mike and Sam Roberts, have been trialling different cover crop mixes for their weaned calves this winter. 94 weaned calves entered the cover crops in mid-November with enough crop to see them through to mid-February, In December they were on two-day moves with one hay bale for roughage. A cold day in December provided a good opportunity to see how they are getting on.

The crops were established through either direct drilling or discing/power harrow drill in late August, the drought through the summer of 2022 delayed establishment and therefore the bulk of the crop. In the spring, these fields will go into a herbal ley reseed with Mike and Sam hoping that the cover crops will have outcompeted much of the weeds, reducing herbicide use, and the cattle will have done some of the initial cultivations. In December the calves were leaving some of the stemmier material and radish bulbs, and attendees discussed the merits of either cultivating this material in to benefit the soil, leaving calves for longer to ensure they eat it (and therefore risking growth rates) or utilising suckler cows to clean up after the priority stock class of the calves. Calf growth rates were to be measured through the winter and spring, with Mike and Sam expecting to see a slow-down in growth through the winter but a faster growth rate in spring as the outwintered calves take less transitioning onto grass than housed animals.

Having a range of plant species in the mixes is done with the ambition to discover which species grow successfully and in sufficient quantity/quality to support the calves through the winter. Species presence/absence was assessed by Dr Hannah Jones from Farm Carbon Toolkit and forage samples were sent for analysis of crude protein, digestibility and other qualities with the results available in the “Grazed winter cover crops” factsheet. Mike and Sam ultimately hope for this crop to be a “standing total mixed ration (TMR)” that could be grazed through the winter without supplementary feeding of silage or hay.

Mike also took time to show the main herd cows outwintering on deferred grass. These were on two-day moves on half a hectare of grass that has been left since August, plus two hay bales which will carry them through to calving in March.

Outwintering at Blable has helped to reduce costs through reductions in time, fuel and feed use through the winter. The outwintering crops greatly reduce the amount of conserved forage fed to the cattle and tractor use is negligible compared to housing where feed is brought to the animals, muck scraped away daily and dirty bedding spread after winter. This has clear corresponding savings in carbon emissions.

Key takeaways

  • Diversity of plant species increases resilience to extreme weather, pests and disease and provides greater diversity of ration for livestock.
  • Outwintering reduces financial costs and reduces carbon emissions from fuel and feed.

This event was made possible with thanks to the National Lottery Community Fund who fund the Farm Net Zero (FNZ) project.

Farm Net Zero resources, events, newsletter

  • To find out more about other previous events, trials and resources produced from the Farm Net Zero project head here.
  • To keep an eye out for future Farm Net Zero events head to our events webpage here.
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